bpf: fix raw_tp test run in preempt kernel (963ec27a) · Commits · 戴 / test

In preempt kernel, BPF_PROG_TEST_RUN on raw_tp triggers: [ 35.874974] BUG: using smp_processor_id() in preemptible [00000000] code: new_name/87 [ 35.893983] caller is bpf_prog_test_run_raw_tp+0xd4/0x1b0 [ 35.900124] CPU: 1 PID: 87 Comm: new_name Not tainted 5.9.0-rc6-g615bd02bf #1 [ 35.907358] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 [ 35.916941] Call Trace: [ 35.919660] dump_stack+0x77/0x9b [ 35.923273] check_preemption_disabled+0xb4/0xc0 [ 35.928376] bpf_prog_test_run_raw_tp+0xd4/0x1b0 [ 35.933872] ? selinux_bpf+0xd/0x70 [ 35.937532] __do_sys_bpf+0x6bb/0x21e0 [ 35.941570] ? find_held_lock+0x2d/0x90 [ 35.945687] ? vfs_write+0x150/0x220 [ 35.949586] do_syscall_64+0x2d/0x40 [ 35.953443] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by calling migrate_disable() before smp_processor_id(). Fixes: ("bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint") Reported-by:

Alexei Starovoitov <ast@kernel.org> Signed-off-by:

Song Liu <songliubraving@fb.com> Signed-off-by:

Alexei Starovoitov <ast@kernel.org>

net/bpf/test_run.c

+9 −12

Original line number	Diff line number	Diff line
		@@ -252,9 +252,7 @@ __bpf_prog_test_run_raw_tp(void *data)
		struct bpf_raw_tp_test_run_info *info = data;

		rcu_read_lock();
		migrate_disable();
		info->retval = BPF_PROG_RUN(info->prog, info->ctx);
		migrate_enable();
		rcu_read_unlock();
		}

		@@ -266,6 +264,7 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
		__u32 ctx_size_in = kattr->test.ctx_size_in;
		struct bpf_raw_tp_test_run_info info;
		int cpu = kattr->test.cpu, err = 0;
		int current_cpu;

		/* doesn't support data_in/out, ctx_out, duration, or repeat */
		if (kattr->test.data_in \|\| kattr->test.data_out \|\|
		@@ -293,27 +292,25 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,

		info.prog = prog;

		current_cpu = get_cpu();
		if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) == 0 \|\|
		cpu == smp_processor_id()) {
		cpu == current_cpu) {
		__bpf_prog_test_run_raw_tp(&info);
		} else {
		} else if (cpu >= nr_cpu_ids \|\| !cpu_online(cpu)) {
		/* smp_call_function_single() also checks cpu_online()
		* after csd_lock(). However, since cpu is from user
		* space, let's do an extra quick check to filter out
		* invalid value before smp_call_function_single().
		*/
		if (cpu >= nr_cpu_ids \|\| !cpu_online(cpu)) {
		err = -ENXIO;
		goto out;
		}

		} else {
		err = smp_call_function_single(cpu, __bpf_prog_test_run_raw_tp,
		&info, 1);
		if (err)
		goto out;
		}
		put_cpu();

		if (copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32)))
		if (!err &&
		copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32)))
		err = -EFAULT;

		out:

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